Assessment of BOMD simulations for the ground-state structure determination of transition metal clusters in the nanometer scale

Abstract

ABSTRACTState-of-the art calculations have been performed for bimetallic transition metal clusters such as Pd19M19 (M=Co and Ni) by employing the linear combination of Gaussian-type orbitals density functional theory (LCGTO-DFT) approach. Structures and energy properties were calculated for these clusters. For each cluster, several dozens of isomers were studied to determine the lowest energy structures. Initial structures for the geometry optimisation were taken along Born–Oppenheimer molecular dynamics (BOMD) trajectories,considering several spin multiplicities. All structures were fully optimised without any symmetry restriction. The optimised structures were characterised by vibrational analysis. Lowest energy structures, relative stability energy, harmonic frequencies, binding energies, vertical ionisation potential, vertical electron affinity and spin density plots are reported. The obtained results are compared with data from the literature. The ground-state structure topology is the same for both clusters. The Pd atoms decorate the surface of the core formed by either Co or Ni atoms. This work demonstrates the importance of using ab initio BOMD simulations to fully explore the potential energy surface of large transition metal clusters.